Means for reversing two-cycle engines.



K. A. NORRMAN.

MEANS FOR REVERSING TWO-CYCLE ENGINES.

APPLICATION FILED NOV. 12. I913.

1,14,042. Patented July 27, 1915.

2 S'HEETSSHEET I.

V Inventor; Karl A. Now-map,

K. A. NORRMAN.

MEANS FOR REVERSING TWO-CYCLE ENGINES.

APPLICATION FILED NOV. 12. 1913- 134,420

Patented July 27,1915.

2 SHEETSQSHEET 2.

C) 30 l7 25 4| l Inverwbr; Karl A. Now-man tinirnn snares "Parana carton.

KARL NORBMAN; 0F LYNN, MASSACHUSETTS ASSIGNOR TO I COMPANY, A CORPORATION OF.NEW YORK.

MEANS FOR REVERSIN G TWO-CYCLE ENGINES.

Specification of Letters 2atent.

Application filed November 12, 1913. Serial No. 800,518.

To all whom it may concern:

Be it known that I, KARL A. NORRMAN, a subject of the King of Sweden, residing at ynn, county of Essex, State of Massachusetts, Improvements in Means for Reversing Two- Cycle Engines, of which the following is a specification. l v

'The present invention relates to means for reversing two-cycle internal combustion engines in which the scavenging pump is utilized for such purpose as an air motor and has for its object to improve and simplify the construction of the controlling mechanism. v

In the accompanying drawings which illustrate one of the embodiments of my invention, Figure 1 is an axial section of a part of an internal combustion engine operating on the high compression cycle; Fig. 2 is a cross-section of the same through the valves controlling the scavenging pump; Fig. 3 is a detailed view showing a modification of the means for admitting scavenging anto the working cylinder, and Fig. 4 is a detail view showing the shapes of the cams ,that actuate the discharge.

' the head is located 5 illustrates the working cylinder which may be of any suitable construction. It is provided with a removable head 6 having a water jacket 7. The cylinder may also be provided with a similar water jacket. In a fuel injector 8 of any suitable construction and the passage of fuel and injection controlled by the needle valve 9. The operating mechanism for the needle valve has been omitted in the interest of simplicity of illustration, but it is to be understood that any suitable form of such mechanism may be employed. Fuel from a suitable source of pressure such the injector by the pipe 10, andthe socalled injection or blast air is admitted by the pipe 11. Located in the cylinder is a piston 12 which is provided with a head 13. On opposite sides of the head and extending inthe direction of the length of the cylinder are ribs or partitions 14 which serve to direct the scavenging air over the top of the piston as flows from the scavhave invented certain new and useful air into the engine isas a pump is admitted to enging'ports to the exhaust ports. Thelpiston is connected to the mai shaft 15 by a connecting rod 16 in any ordinary or suitable manner. one side of the center with exhaust ports 17, Fig. 2, which discharge into a chamber 18, the latter communicating with the conduit 20 leading directly or indirectly to the atmosphere. The cylinder is also provided with scavenging ports 21fon the other side of the center which communicate with a chamber 22, the latter receiving air from the receiver23. Interposed between the receiver and the chamber 22 is a shut-off valve 24 of any suitable construction. The piston 13 is arranged to control both the scavenging and the exhaust ports. operation of the engine the piston uncovers the exhalust ports at the end of the firing stroke and shortly thereafter air is admitted through the ports 21 on the other side from the chamber 22. Owing to the use of the Patented July at, rate.

The cylinder is provided on GENERAL nnncrn' o In the normal ribs 14 on the piston head the air from the ports 21 is caused to flow longitudinally along the cylinder wall in one direction, thence over the top of the piston down the cylinder wall on the other side. In other words, the ribs 14 prevent the scavenging air from flowing directly across the top of the piston fromone side of the cylinder to the other.- This arrangement insures good scavenging which is essential for successful operation. After the cylinder is properly scavenged the piston starts its compression stroke and compresses the air in the cylinder to a temperature above the igniting temperature of the fuel. dead center of the piston the fuel valve 9 is opened and fuel is injected into the cylinder by the socalled blast air.

Situated at one side of the working cylin- At or about the inner der 1s a scavenging pump or air compressor This scavenging pump or compressor may be formed as a part of the same structure as the working cylinder or it may be a the main shaft of the engine in any usual or .Well known manner, forexample by a y cannecting rod 27* and cross-head. As shown the pump is ofthe double acting type, and

is provided with suction or inlet valves 28 at each end and also with discharge valves 29. Since these valves are similar in construction a description of one set, or pair, willbe sufficient. The valves as shown are of the puppet type, although my invention is not necessarily limited thereto. The valves are operatedby bell crank levers 30 and 30 each acting through a collar or abutment 31 on the valve spindle. The bell crank levers 30 and 30 are offset sufficiently to engage the various cams illustrated in Fig. l. The positive operation of the valves is essential to reduce throttling losses, espe\ cially forfast running engines, and should not be regarded as a complication introduced for starting and reversing purposes only. Each valve is provided with a coiled compression spring 32 tending to hold it on its seat. The suction valve'28 is arranged to open inwardly and the discharge valve to open outwardly. The bell crank levers are mounted on suitable brackets 33 and are provided with antifriction rollers 34: that engage the cams on the shaft 35, the latter being rogpated by any suitable driving connection rom the main shaft. On the shaft 35 there are for each pair of pump valves four cams, of which 36 is for the suction valve and 37 for the discharge valve. These suffice for operating the pump and engine in one direction only. The cams for the discharge valves are so shaped as to open said valves only after a certain compression has been attained, say four or five pounds gage for example. The suction valve cams on the other hand are so shaped as to open said valves during the whole stroke of the pump piston. For reverse operation a second set of similar cams 38 and 39 are provided but angularly displaced from cams 36-37 by substantially 180' degrees. Of these 38 is for the suction valve and 39 for. the discharge valve. Each pair of cams is connected by a smooth neck l0 so no difiiculty will he experienced in shifting from one operating condition to another. As shown the discharge valve cams 3739 are located between the suction valve cams. To provide v:lor this the bell crank levers for the former cams are ofiset from those of the latter as indicated in dotted lines in Fig. 1.- It is also to be noted that the cams on the one end of the shaft are angularly displaced by 180 degrees from those on the other end, this being necessary to admit air to the cylinder on one side of the piston when the latter is compressing air on the other side. Air is admitted to the suction valve casing from the chamber 41, 2, which is connected to the atmosphere. After the conr pressed air passes the discharge valves 29 it enters the chamber 42 from which it flows to shaft 35 is supported mas is and is stored in the receiver 23. The cam in suitable bearing brackets 4-3 and is capable of being moved in an axial direction by the hand lever 4-4, the latter being pivoted at and provided with a spring pressed latch to, one end of which is adapted to enter openings L7 in a quadrant or sector 48 and lock the lever in either of its two positions. in order to permit the cam shaft to slide, one oi? its ends enters a square socket in a member #5), the latter being carried by a shaft 50 dri en by the main shaft 15 through suitable gearing.

To the receiver 2? connected a tank 51 commonly known as a. starting bottle and containing highly compressed air. In the pipe connecting the bottle with the receiver is a. shutoli valve In Fig. 3 is shown in section an engine in which the admission ot scavenging air to the working cylinder is controlled by the valve 53 instead of by the working piston as in Fig. 1. This valve may be operated in the usual manner. 3

For simplicity T have shown my invention applied to an engine having only a single working cylinder, but it is evident that many of such cylinders may be pro vided as are desired.

in Fig. 4 is shown a netail view of one of the discharge valves 29 and also the cam 37 for actuating it. The cam 539 for run ning in the reverse direction is indicated in broken and dotted lines.

The operation of the starting mechanism is as follows: When the engine stops some one of the discharge valves 19 will be open, that is to say is in position t let air from the pump pass into the receiver, the suction valve on the corresponding end; i. the one in alinement therewith, being closed. The valve 2% is first closed to shut off the receiver from the scavenging chamber 22 and its ports ill. The valve 52 is then opened and highly compressed air from the tank or bottle 51 flows into the eiver, thence through the valve chamber and past the valve 29 into the pump cylinder where it acts on the iiiston 26 to start it into operation and thus turn. the uuiin shaft and move the working piston It is to be noted that the valve 29 which was the discharge valve for normal operation has under conditions oi starting become the inlet or admission valve. The setting of the cams as heretofore described will under these conditions start the engine backward. Should the engine have stopped before the discharge valve 29 had a chance open it will be necessary to bar the engine over to service. In normal running der these conditions the as an exhaust valve. As this valve remains Should it be desired to trac ea some discharge valve will be open at least enough to turnthe engine to starting position When another valve 29 will freely admit starting air to the pump cylinder.

To start the engine in the normal running direction, it Will be necessary to move the cam shaft toward the main shaft, so that the second set of cams will be put into the discharge valve. 29 opens only after a part of the stroke of the pump piston is completed. in starting, said valve closes after the greater part of the stroke is completed, and which results in a certain degree of expansion of the starting air in the pump cylinder. When the pump cranlrpasses its dead center the suction valve 28 opens and air in the pump cylinderescapes to atmosphere. Un-

suction valve serves open-during the whole stroke stalling of the engine due to compression in the pump cylinder cannot occur.

As soon as the mixture in the Working cylinder is-fired the engine operates under its own power and the valve 52 at the tank is closed and the valve 24 between the receiver and scavenging chamber is opened. bring the engine up to speed or cause it to drive a load before the starting air is shut oil", the valve 24 can be partly. opened so as to allow, by sufhcient throttling, the use of the starting air for scavenging purposes. For reversing, the operations are exactly the same except that lever at is left in the normal running position; 2. When the starting air is admitted.

In accordance with the provisions of the patent statutes, I have described the principle,

of operation of my invention, together with the apparatus which I now consider to rep resent the, best embodiment thereof; but I desire tohave it understood that the apparatus'shovvn is only illustrative, and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. In combination, an internal combustion engine, a scavenging pump driven thereby, a receiver that receives air from the pump and delivers it to the engine during normal operation, valvemeans controlling set of the action of the pump, and a source of fluid under pressure that. supplies fluid to the receiver from Which ll, passes to the pump cylinder for the purpose of starting the engine.

2. In combination, an internal combustion engine, a scavenging pump driven thereby, a receiver that receivesair fromthe pump and delivers it to the normal operation, valve means controlling the action of the pump, sets bf cams for actuating the valves, means for moving one cams or the other into position to 0., that shown,

engine during compressed air to the receiver'from which it passes through the normal discharge valve of the pump into the pump cylinder for starting the engine.

3. In combination, an internal combustion engine, a scavenging pump driven thereby, suction and discharge valves for the pump, cams for them, a receiver that receives compressed air from the pump subject to the controlof the discharge valve and delivers it to the engine during its normal operation, a source of high pressure fluid adapted to supply fluid to the receiver from which it passes through the normal discharge valve of the pump into its cylinder for starting its piston and that of the engine into operation, the suction valve of said pump in the meantime acting as an exhaust valve, and means for controlling the passage of fluid from the receiver to the engine cylinder for scavenging it.

in combination, tion engine, 'a scavenging pump driven thereby, suction and discharge valves for the pumps, a pair of cams for positively actuating each of said valves, one of said cams being angularly displaced With respect to the other, a means for moving one or the other of said came into operative relation to its valve, the pump and delivers it to the engine for scavenging purposes, a valve between the receiver and the engine, and a controllable source of fluid pressure tively actuated valve means controlling the pump.

admission of air to each end of the cylinder and the discharge therefrom, a means for supplying high pressure fluid-to the recei'veiflfrom Which it passes through said valve means to the pump cylinder for starting purposes, and a valve interposed between the receiver and the engine cylinder by means of which thepassage of air to the latter can be controlle 6. In combination, an internal combustion engine, a scavenging pump driven thereby, positively actuated suction and discharge valves for the pump, the suction valve being opened during the'entire suctionstroke and the discharge valve being opened only a receiver and delivers it to the engine during normal operation, and a source of fluid under pres positively actuating" an internal combusand delivers it to the en-.

a receiver that receives air from which is connected to the receiver for admitting fluid-thereto sure that supplies fluicl to the receiver from value]; It passes to the pump 0371111 21% by Way oi the dlschmge Vah'e tor starting the engine, said suction a l v e at such times actmg as: the exhzmeb, and means for cfiseonnectmg the LQCQLZ'VGI ix-0m. the engine.

111 wltness whereef, I have hereunto set KARL A.v NORRMAN.

Witnesses:

JOHN A. MCMANUS, J12, HENRY A. ANDERSEN. 

